scholarly journals Independence of 3D chromatin conformation and gene regulation during Drosophila dorsoventral patterning

2020 ◽  
Author(s):  
Elizabeth Ing-Simmons ◽  
Roshan Vaid ◽  
Mattias Mannervik ◽  
Juan M. Vaquerizas
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Single Cell ◽  
Regulatory Elements ◽  
Chromatin State ◽  
Specific Gene ◽  
Chromatin Conformation ◽  
Dorsoventral Patterning ◽  
Tissue Specific ◽  
Chromatin Organisation

ABSTRACTThe relationship between the 3D organisation of chromatin inside the nucleus and the regulation of gene expression remains unclear. While disruption of domains and domain boundaries can lead to mis-expression of developmental genes, acute depletion of key regulators of genome organisation, such as CTCF and cohesin, and major reorganisation of genomic regions have relatively small effects on gene expression. Therefore, it is unclear whether changes in gene expression and chromatin state drive chromatin reorganisation, or whether changes in chromatin organisation facilitate cell type-specific activation of genes and their regulatory elements. Here, using the Drosophila melanogaster dorsoventral patterning system as a model, we demonstrate the independence of 3D chromatin organisation and developmental gene regulation. We define tissue-specific enhancers and link them to expression patterns at the single-cell level using single cell RNA-seq. Surprisingly, despite tissue-specific differences in chromatin state and gene expression, 3D chromatin organisation is maintained across tissues. Our results provide strong evidence that tissue-specific chromatin conformation is not required for tissue-specific gene expression, but rather acts as an architectural framework to facilitate proper gene regulation during development.

scholarly journals Independence of chromatin conformation and gene regulation during Drosophila dorsoventral patterning

2021 ◽  
Author(s):  
Elizabeth Ing-Simmons ◽  
Roshan Vaid ◽  
Xin Yang Bing ◽  
Michael Levine ◽  
Mattias Mannervik ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Expression Patterns ◽  
Chromatin Organization ◽  
Specific Gene ◽  
Chromatin Conformation ◽  
Dorsoventral Patterning ◽  
Tissue Specific ◽  
Cell Type Specific ◽  
The Relationship

AbstractThe relationship between chromatin organization and gene regulation remains unclear. While disruption of chromatin domains and domain boundaries can lead to misexpression of developmental genes, acute depletion of regulators of genome organization has a relatively small effect on gene expression. It is therefore uncertain whether gene expression and chromatin state drive chromatin organization or whether changes in chromatin organization facilitate cell-type-specific activation of gene expression. Here, using the dorsoventral patterning of the Drosophila melanogaster embryo as a model system, we provide evidence for the independence of chromatin organization and dorsoventral gene expression. We define tissue-specific enhancers and link them to expression patterns using single-cell RNA-seq. Surprisingly, despite tissue-specific chromatin states and gene expression, chromatin organization is largely maintained across tissues. Our results indicate that tissue-specific chromatin conformation is not necessary for tissue-specific gene expression but rather acts as a scaffold facilitating gene expression when enhancers become active.

scholarly journals Chromatin state signatures associated with tissue-specific gene expression and enhancer activity in the embryonic limb

2012 ◽  
Vol 22 (6) ◽  
pp. 1069-1080 ◽  
Author(s):  
Justin Cotney ◽  
Jing Leng ◽  
Sunghee Oh ◽  
Laura E. DeMare ◽  
Steven K. Reilly ◽  
...  
Keyword(s):  
Gene Expression ◽  
Chromatin State ◽  
Specific Gene ◽  
Enhancer Activity ◽  
Tissue Specific ◽  
Tissue Specific Gene ◽  
Specific Gene Expression ◽  
Embryonic Limb

scholarly journals SNPnotes: high-throughput tissue-specific functional annotation of single nucleotide variants

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 1784
Author(s):  
Shraddha Pai ◽  
Michael J. Apostolides ◽  
Andrew Jung ◽  
Matthew A. Moss
Keyword(s):  
Gene Expression ◽  
Gene Mapping ◽  
High Throughput ◽  
Regulatory Elements ◽  
Specific Gene ◽  
Tissue Specific ◽  
Functional Variants ◽  
Genome Regulation ◽  
Organ Systems ◽  
Variant Gene

A key challenge in the application of whole-genome sequencing (WGS) for clinical diagnostic and research is the high-throughput prioritization of functional variants in the non-coding genome. This challenge is compounded by context-specific genetic modulation of gene expression, and variant-gene mapping depends on the tissues and organ systems affected in a given disease; for instance, a disease affecting the gastrointestinal system would use maps specific to genome regulation in gut-related tissues. While there are large-scale atlases of genome regulation, such as GTEx and NIH Roadmap Epigenomics, the clinical genetics community lacks publicly-available stand-alone software for high-throughput annotation of custom variant data with user-defined tissue-specific epigenetic maps and clinical genetic databases, to prioritize variants for a specific biomedical application. In this work, we provide a simple software pipeline, called SNPnotes, which takes as input variant calls for a patient and prioritizes those using information on clinical relevance from ClinVar, tissue-specific gene regulation from GTEx and disease associations from the NHGRI-EBI GWAS catalogue. This pipeline was developed as part of SVAI Research's "Undiagnosed-1" event for collaborative patient diagnosis. We applied this pipeline to WGS-based variant calls for an individual with a history of gastrointestinal symptoms, using 12 gut-specific eQTL maps and GWAS associations for metabolic diseases, for variant-gene mapping. Out of 6,248,584 SNPs, the pipeline identified 151 high-priority variants, overlapping 129 genes. These top SNPs all have known clinical pathogenicity, modulate gene expression in gut tissues and have genetic associations with metabolic disorders, and serve as starting points for hypotheses about mechanisms driving clinical symptoms. Simple software changes can be made to customize the pipeline for other tissue-specific applications. Future extensions could integrate maps of tissue-specific regulatory elements, higher-order chromatin loops, and mutations affecting splice variants.

A modified pod specific promoter for high level heterologous expression of genes in legumes

2019 ◽  
Author(s):  
Aravind Kumar Konda ◽  
Pallavi Singh ◽  
Khela Ram Soren ◽  
Narendra Pratap Singh
Keyword(s):  
Gene Expression ◽  
Regulatory Elements ◽  
Specific Gene ◽  
Specific Expression ◽  
Tissue Specific ◽  
Cis Acting ◽  
Inducible Promoters ◽  
Expression Of Genes ◽  
Enhanced Expression ◽  
High Level

Promoters are cis-acting regulatory elements that are usually present upstream to the coding sequences and determine the gene expression. Deployment of tissue specific and inducible promoters are constantly increasing for development of successful and stable multiple transgenic plants. To this end, as a strategy for enhanced expression of cis or transgenes, promoter engineering of the native msg promoter from soya bean has been carried out for executing pod specific expression of genes. Cis regulatory elements such as 5’UTR and poly (A) tract have been incorporated for imparting mRNA stability and translational enhancement to generate the modified 1.285 Kb pod specific promoter. Further to attain transcriptional enhancement the modified promoter has been cloned to generate Bi-directional Duplex Promoters (BDDP). The engineered msg promoter gene constructs can be deployed for high level tissue specific gene expression of cis/trans genes along with chosen terminator in chickpea. soybean and other legumes as well.

Epigenetics of Cellular Memory: Insights from the Chromatin Accessibility Landscape of the Mitotic Genome

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4342-4342
Author(s):  
Chris C.S. Hsiung ◽  
Christapher Morrissey ◽  
Maheshi Udugama ◽  
Christopher Frank ◽  
Cheryl A. Keller ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Transcription Factors ◽  
Regulatory Elements ◽  
Chromatin Accessibility ◽  
Dnase I ◽  
Specific Gene ◽  
Tissue Specific ◽  
Dnase I Sensitivity ◽  
Mitotic Chromatin

Abstract Normal development requires the coordination of cell cycle progression and gene expression to produce physiologically appropriate cell numbers of various lineages. The concomitant dysregulation of these two cellular programs is central to many malignant and non-malignant hematologic diseases, yet researchers still lack clear, general principles of how intrinsic properties of cell division could influence transcriptional regulation. Mitosis is a unique phase of the cell cycle that dramatically disrupts transcription: chromosomes condense to form microscopically recognizable structures, the nucleus is disassembled, RNA synthesis ceases, and the transcription machinery and many transcription factors are evicted from mitotic chromatin. How cells “remember” tissue-specific transcriptional programs through mitotic divisions remains largely unknown. Some transcription factors, including the erythroid master regulator, GATA1, and certain chromatin features are known to remain associated with DNA during mitosis. These molecular entities have been proposed to serve as mitotic “bookmarks” -- molecules that store gene regulatory information at individual loci through mitosis. However, we have limited knowledge of the composition, mechanism and function of mitotic bookmarks. In this context, chromatin structure deserves special consideration, as chromosome condensation during mitosis could potentially hinder transcription factor binding. To obtain the first genome-wide view of chromatin accessibility during mitosis, we mapped the DNase I sensitivity of the interphase versus mitotic genome in two maturation stages in a murine erythroblast cell line, G1E. Despite microscopic condensation of chromosomes during mitosis, we found that DNase I sensitivity is extensively preserved throughout the mappable genome, indicating that mitotic chromatin is not as condensed as commonly presumed. Individual genes and cis-regulatory elements can maintain all, part of, or none of its interphase accessibility during mitosis, demonstrating that accessibility of mitotic chromatin is locally specified. Promoters generally maintain accessibility during mitosis; moreover, promoters with the highest degree of accessibility preservation in mitosis in G1E cells tend to also be accessible across many murine tissues in interphase. In contrast to promoters, we found that enhancer accessibility is preferentially lost during mitosis, raising the possibility that memory of enhancer regulation may be altered during mitosis. Since enhancers play crucial roles in specifying tissue-specific gene expression patterns, we propose that this phase of the cell cycle may be especially susceptible to resetting of transcriptional programs. This hypothesis is supported by our preliminary results that revealed aberrant RNA polymerase II re-engagement with the genome and transcript production in early G1. Thus, mitosis could be a source of gene expression heterogeneity, with potential implications for cell fate transitions in proliferative cells, such as during stem cell lineage commitment, experimental reprogramming, and tumorigenesis. Disclosures No relevant conflicts of interest to declare.

scholarly journals ATAC-Seq Reveals an Isl1 Enhancer That Regulates Sinoatrial Node Development and Function

2020 ◽  
Vol 127 (12) ◽  
pp. 1502-1518
Author(s):  
Giselle Galang ◽  
Ravi Mandla ◽  
Hongmei Ruan ◽  
Catherine Jung ◽  
Tanvi Sinha ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Transcription Factor ◽  
Sinoatrial Node ◽  
Regulatory Elements ◽  
Right Atrial ◽  
Specific Gene ◽  
Human Populations ◽  
And Function ◽  
Accessible Chromatin

Rationale: Cardiac pacemaker cells (PCs) in the sinoatrial node (SAN) have a distinct gene expression program that allows them to fire automatically and initiate the heartbeat. Although critical SAN transcription factors, including Isl1 (Islet-1), Tbx3 (T-box transcription factor 3), and Shox2 (short-stature homeobox protein 2), have been identified, the cis -regulatory architecture that governs PC-specific gene expression is not understood, and discrete enhancers required for gene regulation in the SAN have not been identified. Objective: To define the epigenetic profile of PCs using comparative ATAC-seq (assay for transposase-accessible chromatin with sequencing) and to identify novel enhancers involved in SAN gene regulation, development, and function. Methods and Results: We used ATAC-seq on sorted neonatal mouse SAN to compare regions of accessible chromatin in PCs and right atrial cardiomyocytes. PC-enriched assay for transposase-accessible chromatin peaks, representing candidate SAN regulatory elements, were located near established SAN genes and were enriched for distinct sets of TF (transcription factor) binding sites. Among several novel SAN enhancers that were experimentally validated using transgenic mice, we identified a 2.9-kb regulatory element at the Isl1 locus that was active specifically in the cardiac inflow at embryonic day 8.5 and throughout later SAN development and maturation. Deletion of this enhancer from the genome of mice resulted in SAN hypoplasia and sinus arrhythmias. The mouse SAN enhancer also directed reporter activity to the inflow tract in developing zebrafish hearts, demonstrating deep conservation of its upstream regulatory network. Finally, single nucleotide polymorphisms in the human genome that occur near the region syntenic to the mouse enhancer exhibit significant associations with resting heart rate in human populations. Conclusions: (1) PCs have distinct regions of accessible chromatin that correlate with their gene expression profile and contain novel SAN enhancers, (2) cis -regulation of Isl1 specifically in the SAN depends upon a conserved SAN enhancer that regulates PC development and SAN function, and (3) a corresponding human ISL1 enhancer may regulate human SAN function.

scholarly journals Tissue-specific 5-hydroxymethylcytosine landscape of the human genome

2020 ◽  
Author(s):  
Bo He ◽  
Chao Zhang ◽  
Xiaoxue Zhang ◽  
Yu Fan ◽  
Hu Zeng ◽  
...  
Keyword(s):  
Gene Expression ◽  
Human Genome ◽  
Genome Wide Association Study ◽  
Regulatory Element ◽  
Regulatory Elements ◽  
Specific Gene ◽  
Epigenetic Mark ◽  
Human Tissues ◽  
Tissue Specific ◽  
Regulatory Functions

Abstract 5-Hydroxymethylcytosine (5hmC) is an important epigenetic mark that regulates gene expression. Charting the landscape of 5hmC in human tissues is fundamental to understand its regulatory functions. Here, we systematically profiled the whole-genome 5hmC landscape at single-base resolution for 19 types of human tissues. We found that 5hmC preferentially decorates gene bodies and outperforms gene body 5mC in reflecting gene expression. Approximately one-third of 5hmC peaks are tissue-specific differentially hydroxymethylated regions (tsDhMRs), which are deposited in regulatory elements that regulate the expression of nearby tissue-specific functional genes. In addition, tsDhMRs are enriched with tissue-specific transcription-factor-binding sites and may rewire tissue-specific gene expression networks. Moreover, tsDhMRs are associated with SNPs identified by genome-wide association study (GWAS), linked to tissue-specific phenotypes and diseases. Collectively, our results show the tissue-specific 5hmC landscape of the human genome and demonstrate that 5hmC serves as a fundamental regulatory element affecting tissue-specific development and diseases.

scholarly journals A sequence-based global map of regulatory activity for deciphering human genetics

2021 ◽  
Author(s):  
Kathleen M Chen ◽  
Aaron K Wong ◽  
Olga G Troyanskaya ◽  
Jian Zhou
Keyword(s):  
Gene Expression ◽  
Large Scale ◽  
Human Genetics ◽  
Regulatory Elements ◽  
Specific Gene ◽  
Sequence Information ◽  
Regulatory Activity ◽  
Tissue Specific ◽  
Regulatory Architecture ◽  
Sequence Class

Sequence is at the basis of how the genome shapes chromatin organization, regulates gene expression, and impacts traits and diseases. Epigenomic profiling efforts have enabled large-scale identification of regulatory elements, yet we still lack a sequence-based map to systematically identify regulatory activities from any sequence, which is necessary for predicting the effects of any variant on these activities. We address this challenge with Sei, a new framework for integrating human genetics data with sequence information to discover the regulatory basis of traits and diseases. Our framework systematically learns a vocabulary for the regulatory activities of sequences, which we call sequence classes, using a new deep learning model that predicts a compendium of 21,907 chromatin profiles across >1,300 cell lines and tissues, the most comprehensive to-date. Sequence classes allow for a global view of sequence and variant effects by quantifying diverse regulatory activities, such as loss or gain of cell-type-specific enhancer function. We show that sequence class predictions are supported by experimental data, including tissue-specific gene expression, expression QTLs, and evolutionary constraints based on population allele frequencies. Finally, we applied our framework to human genetics data. Sequence classes uniquely provide a non-overlapping partitioning of GWAS heritability by tissue-specific regulatory activity categories, which we use to characterize the regulatory architecture of 47 traits and diseases from UK Biobank. Furthermore, the predicted loss or gain of sequence class activities suggest specific mechanistic hypotheses for individual regulatory pathogenic mutations. We provide this framework as a resource to further elucidate the sequence basis of human health and disease.

scholarly journals Role of ZBP-89 in human globin gene regulation and erythroid differentiation

Blood ◽  
2011 ◽  
Vol 118 (13) ◽  
pp. 3684-3693 ◽  
Author(s):  
Andrew J. Woo ◽  
Jonghwan Kim ◽  
Jian Xu ◽  
Hui Huang ◽  
Alan B. Cantor
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Globin Gene ◽  
Erythroid Differentiation ◽  
Regulatory Elements ◽  
Specific Gene ◽  
Specific Gene Expression ◽  
Erythroid Maturation ◽  
Globin Gene Regulation

Abstract The molecular mechanisms underlying erythroid-specific gene regulation remain incompletely understood. Closely spaced binding sites for GATA, NF-E2/maf, and CACCC interacting transcription factors play functionally important roles in globin and other erythroid-specific gene expression. We and others recently identified the CACCC-binding transcription factor ZBP-89 as a novel GATA-1 and NF-E2/mafK interacting partner. Here, we examined the role of ZBP-89 in human globin gene regulation and erythroid maturation using a primary CD34+ cell ex vivo differentiation system. We show that ZBP-89 protein levels rise dramatically during human erythroid differentiation and that ZBP-89 occupies key cis-regulatory elements within the globin and other erythroid gene loci. ZBP-89 binding correlates strongly with RNA Pol II occupancy, active histone marks, and high-level gene expression. ZBP-89 physically associates with the histone acetyltransferases p300 and Gcn5/Trrap, and occupies common sites with Gcn5 within the human globin loci. Lentiviral short hairpin RNAs knockdown of ZBP-89 results in reduced Gcn5 occupancy, decreased acetylated histone 3 levels, lower globin and erythroid-specific gene expression, and impaired erythroid maturation. Addition of the histone deacetylase inhibitor valproic acid partially reverses the reduced globin gene expression. These findings reveal an activating role for ZBP-89 in human globin gene regulation and erythroid differentiation.

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